Method of constructing besistance-gbids



C. E. OGDEN. METHOD OF CONSTRUQCTINYG RESISTANCE GRIDS.

APPLICATION FlLED MAR. 21, 1919'.

1,316,321; K 'laiented Sept. 10, 1919.

qmq b A ZZVLQJZ for) CLARENCE E. OGDEN, OI CINCINNATI, OHIO.

METHOD OF GONSTRUCTING RESISTANCE-GRIDS.

Specification of Letters Patent.

Patented Sept. 16, 1919.

Application filed March 21, 1919. Serial- No. 284,156.

To all whom it may concern.

Be it known that I, CLARENCE E. OGDEN, a

. citizen'of the United States, and a resident of Cincinnati, in the county of Hamilton, in the State of 'Ohio, have invented a certain new and Improved Method of Constructing Resistance-Grids, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to the construction of resistance grids.

The principal object of the present invention is to provide a simple and inexpensive method for the construction of resistance grids, so that perfect contacts will be made between the respective grids when the same are arranged in banks. Resistance grids, as they come from the molds, are, in common with similar castings, covered with a scale imperfect contact and resultant arcing between adjacent grids when arranged in banks. In the preparation of such grids for smooth surfaces.

banking, it has heretofore been the practice to grind contacting portions 0 as to present Such surfaces, however, are required to be disposed in parallel planes in order that adjacent grids may be evenly banked and the contacting surfaces perfectly joined. This requires great accuracy of work, and any inaccuracy in the result will cause imperfect contacts. It is to overcome these defects and the necessity for ac curacy of machining that the present invention is principally designed.

It has furthermore been the practice heretofore in numerou instances, in order to give to resistance grids a finished appearance, to provide a coating of aluminum or other paint. Such paint when the grid is placed in operation is productive of unpleasant odors and the application of the same is initially of considerable-expense. A further object of this invention is to give to the grids a finished and attractive appearance without the requirement for specially painting the same, the result being achieved more economically during the preparation of the grids for perfect contacts when arranged in banks.

Further objects of the present invention will appear from the following detailed description thereof.

In the drawings: a Figure 1 i an elevation of a resistance grid.

Fig. 2 is an end elevation of a series of grids arranged in banks to illustrate the contacts. I

The numeral 1 indicates a cast iron grid of any preferred design and shape, the same being provided with eyes 2. The sides of the eyes 2 form bosses or faces 3 which form the contacts between adjacent grids when banked, insulating bushings 4 being inserted through the eyes to insulate the grids from the usual coupling bolts 5.

It is to the preparation of the faces 3 for such perfect contacts that the present invention is principally directed. As received from the molds said faces are covered with a scale, which, according to the present practice, it is found necessary to remove by niachining the faces. In order to obviate the necessity for such work, in carrying out the present method, I cover the faces or the entire grid with a coating of metal of substantially like resistance to that of the iron of which the grid is composed. This is done preferably by nickel-plating the grid, especially the "faces 3 of the eyes. The faces 3 so prepared present entirely smooth surfaces which, when the grids are banked and bolted together, make perfect contacts between the grids, and this result is accomplished, as will be seen, without the necessity for any machine work whatever, the nickel-plating providing the necessary smooth surfaces on the contacting portions of the grids, which have, of, course, been made in the proper parallelism in the founders molds.

An incidental advantage achieved by this method of construction and preparing grids resides in the fact that by nickel-plating grids thcsame are provided with a Surface of neat and attractive appearance, thus ob viating the necessity for applying a coating of aluminum or other paint. The nickelplating when applied is also permanent and the heating of the grid does not produce any offensive odors, nor does it mar or cause the finish to deteriorate.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

l. The method of constructing resistance grids comprising the forming of grids with surfaces properly disposed to'm'ake contact between adjacent grids when banked, then providing the contact portions of said wide with a, coating of material of substantlally 5 like resistance to that of the material of which the grids are formed. r

2. The method of constructing resistance grids comprising the forming of grids with surfaces properly disposed to make contact between adjacent grids when banked, then 10 nickel-plating the contact portions of said grids.

CLARENCE E. OGDEN. 

